1. Field of the Invention
The present invention relates to an encapsulating sheet, a light emitting diode device, and a producing method thereof, to be specific, to an encapsulating sheet, a method for producing a light emitting diode device using the encapsulating sheet, and a light emitting diode device produced by the method.
2. Description of Related Art
A light emitting diode device is, for example, provided with an LED (a light emitting diode element) which is mounted on the upper surface of a board and emits blue light, a phosphor layer which is capable of converting the blue light into yellow light and is provided on the LED, and an encapsulating layer which encapsulates the LED. The light emitting diode device emits high-energy white light by color mixing of the blue light, which is emitted from the LED that is encapsulated by the encapsulating layer and transmits through the phosphor layer, and the yellow light, which is converted in wavelength from a part of the blue light in the phosphor layer.
As a method for producing the light emitting diode device, the following method has been proposed (ref: for example, Japanese Unexamined Patent Publications No. 2009-60031 and No. 2010-123802).
That is, in Japanese Unexamined Patent Publication No. 2009-60031, first, an integrated-type encapsulating sheet is prepared. The integrated-type encapsulating sheet includes a resin sheet A (a first layer) that is prepared from an epoxy resin and is formed with a hole and a resin layer B (a second layer) that is formed by pouring a silicone varnish containing a phosphor and a silicone gel into the hole in the resin sheet A. Next, the integrated-type encapsulating sheet is laminated on a board on which an LED element is mounted so that the second layer is brought into contact with the LED element to be subsequently subjected to a thermal compression bonding and then, a post curing. In this manner, an optical semiconductor device is obtained.
Also, in Japanese Unexamined Patent Publication No. 2010-123802, first, a first resin layer which is prepared and formed from a solution containing a phosphor and a silicone elastomer is laminated on the entire surface of a second resin layer which is prepared and formed from a silicone resin solution, so that a semiconductor encapsulating sheet is prepared. Next, the semiconductor encapsulating sheet is put on a board on which an LED chip is mounted so that the second resin layer in the semiconductor encapsulating sheet is brought into contact with the LED chip to be subsequently subjected to a thermal compression bonding and then, a post curing. In this manner, an optical semiconductor device is obtained.